专项:情态动词 一 考点: 情态动词的用法和辨析,情态动词表示推测和可能,由情态动词引导的一般疑问句的回答。 二 类型:1 只是情态动词:can, could, may, might, must 2 可做情态动词,可做实义动词:need, dare 3 可做情态动词,可做助动词: will, would, shall, should 4 特殊:have to, ought to, used to 三 特征:1 有一定的词义,但不能单独作谓语,必须与行为动词和系动词连用构成谓语。 2 无人称和数的变化。(have to 除外) eg: he has to stay here. 3 后接动词原形。 4 具有助动词作用,可构成否定,疑问或简短回答。 四 用法: 1. can ① 表示能力,“能,会”。eg : can you play basketball? ② 表示怀疑,猜测,常用于否定句或疑问句。 eg :li hua can’t be in the classroom. ③ 表示请求,允许,多用于口语,译“可以”= may. eg: you can go now. ④can 开头的疑问句,肯定句,否定句用can或 can’t. 2.could ①can 的过去式,表示过去的能力。 eg :i could swim when i was seven years old. ②could 开头的疑问句,肯定和否定回答用could, couldn’t如果could 表示现在的委婉,用can 回答。 eg: could i have a drink? yes, you can. 3.may ① 表示推测,“可能,也许”,用于肯定句。 eg: he may come tomorrow. ② 表示请求,“许可,可以”。eg:may i borrow your book? 注:表示请求,许可时,主语为第一人称的一般疑问句,否定回答用mustn’t“不可以,禁止,不许”,不用may not“可能不”。 ③表示祝愿。eg :may you success. 4.might ①表示“可以”,用于过去时中。 eg: he told me i might smoke in the room. ②用于现在时,表示说话更委婉,礼貌。 eg:he might be doing his lessons now. 5.must ①表示“必须,应该”。 ②表示推测“一定”。 eg:there is someone knocking at the door.it must be jim. ③否定句中,mustn’t 表示禁止,“不允许”。 ④以must 开头的疑问句,肯定句回答用must,否定回答用needn’t , 表示“不需要,不必”=“don’t have to”. ⑤表示“偏偏”。eg: must you play the piano at this time. 6.need ①情态动词:+do,用need 提问或回答,肯定句回答用must ,否定句回答用needn’t. eg: you needn’t come to school so early. ②实义动词:+to do ,用助动词提问和否定。 ③+doing 表示被动。 ④needn’t have done 表示没必要做某事但是做了。 eg: i actually needn’t have bought so much wine. 7.dare ①情态动词,多用于疑问句,否定句,条件句中。 eg: i’m afraid you dare not to do such a thing. 注:i dare say 习惯说成“也许,我想”。 eg: it will rain this afternoon, i dare say. ②实义动词:dare to do ,用于肯定句中,当用于否定句或疑问句时,to 可以省略。eg: this student doesn’t dare to raise any question in class. 8.shall ①用于第一人称表示征求意见,询问。 eg: shall i open the window? shall we have lunch here? ②表示说话人的态度,“命令,警告,允诺,威胁”。 eg: you shall finish your homework first. ③用于第三人称,在条约,规定,法令等文件中表示义务或规定,“应该,必须”。(不常用) 9.should ①表示义务,责任“应该”。eg:we should obey traffic laws. ②作为shall 过去式,用于第一三人称,表示征求意见。eg:mr lee asked if he should get his visa. ③表示“竟然”。 eg: it’s unthinkable that the boy should sing such a beautiful song. ④表示说话人的特殊情感,如惊奇,愤怒,失望等。 eg: how should i know? ⑤表示劝告,建议,“应该”。 eg: you should listen to your teacher. 10.will ①用于第二人称表示询问,请求,也可以表达现在的“意愿”。eg: will you pass me the book? ②表示意愿,决定,允诺,用于各种人称。 eg: i will try my best to help you. ③表示规律性的“注定会”。 eg: people will die without air or water. 11.would ①表示过去的意愿或委婉询问。 eg: would you tell me the way to the station? 12.have to ①“必须,不得不”,强调客观需要,含有时态的变化。 eg: i’ll have to ask jim instead. ②区别:must 表示“必须,应该“,主观看法。 13.ought to ①表示职责,义务或要求,及人们应该去做的正确的事或好事。eg: humans ought to stop polluting nature. ②比should 语气强,ought to 反映客观情况,should表示主观看法。 ③ought to have done 本应该做而没有做。 eg: you are late. you ought to have arrived five minutes earlier. 14.used to ①表示“过去常常,过去是“,没有人称和数的变化,可以和过去的时间状语连用。否定形式:usedn’t to 或didn’t use to ,疑问词将use提前或did…use to …? eg: he didn’t use to be so careless. ②区别 would :带有主观性,并且现在做不做不知道。used to :客观性,和现在进行对比,过去常常,现在就不怎么做了。 eg: he would phone me on sunday. eg: i used to be very fond of music when i was young. ③区别:be used to doing (情态动词)习惯于… used to do (情态动词)过去是,过去常常… be used to do (过去式) 被用来做… eg: i am already used to noisy city life here. my parents used to live in south america. this machine is used to cut up waste paper. 15.其他:⑴had better do 最好做某事 eg: you had better stay at home. 否定:had better not do ⑵be able to 与can 表示能力时用法相同,但前者有时态的变化,有能力成功做某事。 eg: we will be able to come back next week. 专题练习:
1( ) 1 john___ come to see us tonight, but he isn't very sure yet.
a. mustn't b. needn't c. don't have to d. don't need to
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来自: wuming0717 > 《初中英语》